The sight according to the invention is intended to be used instead of open sights of the conventional type which are mounted on such weapons, and has for its purpose to simplify the aiming procedure, to facilitate target practising by using a simpler aiming method which is easy to learn, and to increase the percentage of hits when firing at mobile targets in daylight and at all kinds of targets in darkness. The sight according to the invention is intended to be used according to the same principle as open sights, i.e., by finding the aiming-line over the sights, contrary to what is the case with optical sights, where the target is observed through a telescope or another similar optical instrument giving an enlarged image of the target, whereupon the aiming proper is done with the aid of e.g. crosshairs or other suitable markings on the sight.